The whole bug story is avail. at http://bugs.debian.org/431696.
Basically, a segfault happened to our user when he tried to update a driver from a Windows client.
In the bug log, Jelmer Vernooij finally made the following analysis:
"We were freeing the files structure for the old file twice when opening the new file
failed."
He provided a patch that doesn't seem to be applied in 3.2.4 yet. I'll attach it here.